Human chromosome 5 contains a number of genes involved in normal growth and development, particularly of the hemopoietic system. Severl of these genes are clustered on the long arm of chromosome 5, in the region 5q3l-32. The relative positions of most of the genes is not known nor is the significance of this clustering understood. It is known that this region is frequently deleted or rearranged in diseases of hematopoietic development or malignancy of the hematopoietic system. It is proposed in this application that a large portion of this region be cloned and physically mapped. The boundaries of the region chosen for this analysis are defined by the genes for four cytokine molecules. The genes for interleukin 3(IL-3), interleukin 4(IL-4), interleukin 5(IL-5), and granulocyte macrophage- colony stimulating factor(GM-CSF) have been mapped to 5q3l-32 and are clustered in two pairs. IL-3 and GM-CSF are within 9kb of each other and IL-4 and IL-5 are within 90kb of each other. The distance between the two pairs of loci is not known but is likely to be greater than 5OOkb and less than 2,000kb. Yeast artificial chromosome(YAC) clones spanning this region, and the immediately surrounding area, will be isolated from a highly redundant YAC library. Modified PCR protocols will be developed to allow rapid walking in the YAC library. The inserts from these clones will be physically mapped with respect to location of sites for relatively rare cutting restriction enzymes and the location of the cytokine genes and other genes known to map to this area. New and conventional approaches to the identification of previously unknown genes will be used to complete the map and further define the synteny. Completion of this project will result in a detailed map of this region of chromosome 5 and will provide clues as to the molecular basis of hematopoietic disorders and malignancy. Additionally, the new technology developed during the course of this investigation will facilitate the rapid isolation and mapping of large regions of the human genome and the rapid identification of coding regions.